New Delhi: Incessant heavy rains on Sunday led to waterlogging at IGI airport, causing inconvenience to passengers who waded through knee deep water while the baggage handling system was left crippled.

The monsoon arrived in Delhi on Sunday a fortnight ahead of schedule, with national capital recording around 36.6 mm rainfall. But the airport witnessed an "unprecedented" rainfall of 117.8 mm in four and half hours, between 1 PM and 5.30 PM.

The airport experienced 62.8 mm of rains between 1 PM and 2.30 PM and 55 mm between 2.30 PM and 5.30 PM. The amount of rain water, combined with poor drainage in the surrounding area and topography of airport led to back flow of water towards the Terminal 3 of the airport.

"Incessant rains, poor drainage system in surrounding area and comparative low elevation of the airport led to back flow of water, which led to flooding at terminal area," an airport official said.

Services at the domestic arrivals were the most affected due to flooding which forced the airport authorities to close the functioning of four baggage belts, causing inconvenience to passengers.

Flight schedule was, however, unaffected. According to sources, there was knee deep water near the exit of Airport Express Metro and passengers had to wade through it to reach the terminal.

Earlier, the airport had witnessed similar incident of flooding in September 2011, when airport area received 115.6 mm of rains in just 75 minutes, between 2.30 PM and 3.45 PM.

As the water entered the terminal building, the airport operator Delhi International Airport Limited (DIAL) pressed emergency workers into action to drain the water out of the terminal.

"The rain water had entered in international and domestic arrival halls. The waterlogging affected normal passenger movement," a source said "There was heavy waterlogging between 2-5 PM inside the arrival halls of the airport," the source said.

The situation was brought under control only late in the evening. Sources said that DIAL had written to civic agencies like PWD and municipal body for providing adequate drainage in the surrounding areas but the work started late and airport had to face such a situation.

DIAL spokesperson said that in view of poor drainage in surrounding areas and the comparatively low elevation of the airport, on Sunday's heavy rainfall led to back flow of water towards the terminals.

"Due to adequate capacity of all services, operations remained normal," he said. Local authorities have recently started work on augmenting drainage facilities in surrounding areas. Upon completion, it is hoped the said drainage works will stem the back flow of water and prevent the recurrence of incidents like today, he added.